Roofing and process of manufacturing same



Patented Aug. 29, 1933 1,924,181 ROOFING AND raoonss or mnemo- TUBINGSAME Roger w. Cutler, Needham, Mass.

No Drawing. Application June 16, 1928 Serial No. 286,063 1 4 Claims.(01. %-2) This invention relates to roofing and to processes ofmanufacturing roofing.

At the present time the better grades of fireproof roofings arerelatively expensive while the cheaper grades of roofing, with theexception of metal roofing, are not fireproof. Metal roofing is notsuitable as a rule for use on residential buildings, although it finds avery wide and important use in industrial buildings, farm buildings, andthe like. these uses are in its tendency to corrode and its lack ofmechanical strength except in heavy gauges.

The present invention aims to devise a roofing which can be manufacturedat a sufiiciently low cost to compete successfully with the cheapergrades of roofings, but which .will be superior to them and will have amuch wider range of usefulness.

In building certain types of structures, such as sheds and a greatvariety of the buildings used in warmer climates, it is desirable toerect a frame and then nail the roofing directly to the frame timberswithout boarding the roof.

To satisfy these requirements a roofing must be very strong mechanicallyin addition to being waterproof and substantially fireproof. It is,therefore, a further object of this invention to devise a roofing whichwill be more satisfactory for this purpose than the roofings heretoforeavailable.

It is contemplated that the product provided by this invention can be"used either in the form of sheet roofing, whether corrugated br .fiat,shingles, or for siding, and all of these articles therefore will beincludedjn this specification and in the appended claims in the term"roofing.

Price considerations make it essential to use relatively inexpensivematerial for the body of the roofing. For this reason I prefer to usesomeinexpensive form of fibre such as wood pulp, pulp screenings, orequivalent materials. with this fibrous stock I preferto mix asubstantial proportion of some powdered or granular non-combustiblesubstance, such as gypsum, clay and sand, or the like. These and similaringredients constitute the body forming materials for the roofing. Withthem is mixed a non-combustible binder such as Portland ce- -ment, ormore preferably, potassium or sodium .silicate.

The desired degree of resistance to combustion may be imparted to theproduct partly by the use of the non-combustible ingredients above Itschief disadvantages for mentioned and partly, also, by'the use offireproofing'salts, such as borax, ammonium chloride, ammonium sulphate,ammonium phosphate, aluminum sulphate, and even common salt in smallproportions. Preferably a mixture of ammonium chloride, -or ammoniumsulphate and borax is used since a mixture of these salts appears toneutralize the objectionable characteristics of the ammonium salts,while at the same time producing a combination which has goodfireproofing properties and is relatively inexpensive. Ammonium chlorideor ammonium sulphate if used alone are objectionable because of theirtendency to corrode the metals with which they come in contact includingthe nails driven through the roofing to hold it in place. If borax isusedeither with ammonium chloride or ammonium sulphate it seems tosubstantially neutralize this tendency and certainly greatly minimizesthe corrosive action of te ammonium salts.

' Itis necessary to work these materials into the form ofa sheet orboard and this may conveniently be done by mixing the salts with thebody forming materials and rolling or molding and pressing the mass toform a sheet or board.

A method of procedure, however, which I consider preferable is to placethe body forming materials and the binder in a beater, such as that usedin the paper industry, and to beat them in a solutionof thefirepr'oofing salts.

This results in suspending the fibrous and granular constituents in thesolution, and the beaten mixture can then be delivered to a boardforming machine, such, for example, as the so-called cylinder machinesused in making binders board, fibre board, and paper boards of variouskinds. The solution can be reused, additional salts being addedto keepthe concentration sub- 9 stantially uniform.

The proportions of the ingredients used necessarily will vary somewhatwith the composition of the mixture, the nature of the ingredients used,and the results desired. If a very high percentage of wood fibre or pulpof a combustible nature is used, it may be advisable to use such a,concentration of salts in the solution that approximately 20% of theweight of the board when dry will consist of salts. This 105 percentage,however, is rather higher than or-' dinarily is required. In a typicalcase the weight of the dry board may consist approximately of 35% to40%, by weight, of fibrous constituents, about 15% of fireproofingsalts, and approximately 50% of non-combustible ma- ,/least for manypurposes, to use one of the cresol base resins, such for example, asthat v essential that a through and through impregnaknown commerciallyas catalin. The resin may be applied by spraying or dipping, the resinbeing dissolved in a solvent, such for example, as denatured alcohol.Preferably the dry board is dipped in a solution of the resin, thesolution penetrating rapidly because of the relatively porous nature ofthe board. It is not usually tion be produced, but the strataof theboard for a-substantial depth should be impregnated. If catalin varnishis used it will be found to penetrate very rapidly so that a very briefdipping produces an entirely satisfactory impregnation. This and theother synthetic resins make excellent binders and could be usedexclusively for this purpose if it were not for considerations of price.At the present time, however, even the cheapest of these resins is tooexpensive to use alone as a binder, and it is for this reason thatsodium silicate is preferred as a binder, this material producing a verystrong board and having desirable fireproofing properties, while at thesame time being of valuable assistance in reducing the quantity orsynthetic resin which will penetrate the board.

The resin at this time is in an intermediate phase, that is, in-theso-called A or B stages, preferably the latter. The next step in,theprocess, therefore, is to heat the impregnated body to convert thesynthetic resin into its C stage where it is insoluble in water and issubstantiallyinfusible. In performing this operation it is preferable tokeep the heat at arelatively low point, at least for a time, in order toavoid breaking down the fireproofing salts and driving them off.Assuming that the catalin varnish is used as the waterproofing agent, itis preferable not to raise the temperature above 180- F. In fact, theentire conversion of the resin can be accomplished at lower temperatureswithin three or four hours. Only a relatively small percentage, say 5%,of resin is required, such percentage being based on the weight of thefinal product. To convert this small percentage of resin the temperaturecan well be started at, say, 130 F. and later raised to 180. F. afterthe resin in the outer strata of the board has been converted and thefireproofing salts consequently have been sealed in.

The synthetic resin makes the board highly waterproof, gives itexcellent wearing qualities, and, if a penetration of the resin for asubstantial depth is permitted, it adds materially to the mechanicalstrength of the board.

Prior to either. the impregnating or heating operations, the board maybe pressed, cut, or f otherwise shaped. Preferably this operation isperformed before the impregnating step. so that the scrap or refuse canbe returned-to the beat: er and utilized. Roofing and siding of anydesired form can be made by this process. Itmay take the form ofshingles or shingle strips in any desired shapes and either plainor-tapered butt shingles may be made this way. Any of the usual types ofsidings also can be manufactured'by this process.

In making sheet roofings for many purposes, particularly those intendedto be nailed directly to .the frame timbers of a building, it ispreferable to corrugate the board in much the manner that metal roofingsare corrugated in order to'give additional strength to the sheets.Preferably the corrugations are two and one-half or three inches betweencenters and about fiveeighths of an inch deep, and such shaping of thematerial produces an exceptionally strong roofing. It also has theadvantage of being very resilient. This is particularly true when sodiumsilicate is used as a binder, this being the material preferred for'this purpose. It makes a board of great mechanical strength and thecorrugating of the board. adds materially to its tively high degree offireproofness. As above indicated, this result is obtained partly by thegranular materials used in its composition, partly, also, by the natureof the fireproofing salts which it includes, and in addition, both thesodium silicate binder and the synthetic resin waterproofing agentcontribute to this result.

It should also be noted that the salts have toxic properties and thatthe binding and waterproofing materials are of such a nature that theroofing is. rendered practically immune from the attacks of insects orof fungi which would produce decay. Both these are particularlyimportant advantages where the roofing is to be used in tropicalcountries. Decay proceeds very rapidly in such climates and certaininsects, more particularly ants, would attack the roofing and destroy itin a very short time if it were not for the protection afforded by thesesubstances. I

The roofing produced by this invention is stronger mechanically thansheet metal roofings of the ordinary gages, is lighter in weight, easierto handle, more resilient, and has a longer life. It is also superior tothem in that it does not require painting. If desired pigments can bemixed with the fibre in the beater to produce the desired colors.manufactured to meet a great variety of uses and the manufacturing costcan be held within entirely reasonable limits;

Having thus described my invention, what I desire to claim as new is:

roofing provided by this invention is its rela- The roofing thus can he13. 1. A roofing of the character described, com- 1 prising a bodycontaining a high proportion of combustible fibrous material united-by afireproofing binder and coated with an additional waterproofingsubstance which is relatively bfittle at high atmospheric temperatures.

-2. That improvement in processes ofmanufacturing a roofing whichconsists in suspending body forming materials in a solution of fire- 3.That improvement in processes oi manufacturing roofing which consists inproducing a sheeted fibrous body containing substantial proportions offireproofing salts and a synthetic resin in one of its lower phases,said resin being present in suificient proportions to render said bodysubstantially waterproof, heating the body so produced at a relativelylow temperature to convert the resin in the outer strata of the bodyinto an insoluble condition and thereby to seal said salts into thebody, subsequently raising the temperature of said body and therebyproducing a conversion of said resin in the deeper strata oi the bodyinto an insoluble condition, and continuing such heating until all ofsaid p 3 resin for a substantial depth in the body h been so converted.

4. A roofing oi. the character described comprising combustible fibrousmaterials mixed with ranular non-combustible materials associated ROGERW. CUTLER.

